The Unexpected Niece
by Lord Potterlock
Summary: Mycroft has to go out of town for a bit. That's not unusual, right? Wrong. What happens when Sherlock has to baby sit a teenager that could pass as his daughter? Crime solving, action filled days of course! Mostly OC-centric. Sort of. OoC-Sherlock. (Taken from my tumblr: life-is-righteous)
1. Ella Kane

**Mycroft has to go out of town for a bit. That's not unusual, right? Wrong. What happens when Sherlock has to baby sit a teenager that could pass as his daughter? Crime solving, action filled days of course! Mostly OC-centric. Sort of.**

"No," Sherlock says flatly. "It is of high importance, brother mine. I—,""My answer is quite clear, brother mine. I will not baby sit," Sherlock interrupts.

"It's not babysitting if I'm not an actual baby," the curly haired girl mutters to herself.

John snorts, trying to contain his laughter while Sherlock glares at her.

"Then how old are you?" Sherlock asks.

"17. Why am I here, Mycroft? Mother sent me to stay with you not your little brother. Is there some type of national security breach? I've always stayed with you over the summer and all of a sudden you shut me up with your brother. Something has changed," the girl replies looking at the elder Holmes.

She's 5'5" give or take an inch. Her clothes are that of a middle class family but she isn't given the fact that she stays with Mycroft during the summer. Very high class since it's Mycroft, the British government. Her family must be one of the higher ups. Just below the queen.

Born and raised in Cardiff but travels in her own car in and out of London. Wavy black hair, bright blue eyes that tend to change color (Heterochromia iridum), has a straight but slightly turned up nose, with Cupid bow lips and easy seen dimples.

Retains a tattoo on the inside of her right wrist. One backwards K and a normal K together. That is the insignia of. "A Kane. You're a Kane. The last child," Sherlock finally speaks.

Ella smirks from where she's sitting which just so happens to be John's chair. When they first arrived, Sherlock and John were not home but Mrs. Hudson insisted that the boys would be back shortly and invited them to go right on up. That's how Sherlock and John found them. The Kane girl sitting on John's chair and Mycroft standing by the fireplace.

"Ella Kane at your service. Judging by your earlier silence, you've already deduced me. Go on then. I want to hear it. Father always talked about how amazing it was," Ella replies, smiling. Mycroft shifts slightly, proudly.

"Well, as you know, I've already deduced that you're a Kane judging by the fact that you have stayed with Mycroft over the past summers and the fact that you have the Kane tattoo in the inside of your wrist. You have your own car and drive in and out of London from Cardiff. You own no pets and have Heterochromia iridum. That means your eyes have two sets of color in them so your eye color changes just like mine. Judging by your tone, you don't understand what you're doing here and you'd rather be with Mycroft in his home. Why is that? Why would anyone want to stay with Mycroft? That's absurd!" Sherlock exclaims.

"Let's just say we're family by marriage," Mycroft replies. Sherlock squints at him and his eyes widen in shock.

"You're married to her mother?" Sherlock chokes out. "Well, I've lied again. We're soon to be married. Engaged but not married. This is my step daughter and your niece. Well, soon to be I suppose," Mycroft says. "What happened to caring is not an advantage?" Sherlock asks. "I've come to a conclusion that sometimes caring can be the best advantage there is," Mycroft says, smiling fondly down at Ella. She smiles up at him.

"So long how then?" John asks. "They've managed to keep quiet for three years. People see but they don't observe, otherwise they would've suspected something since I visit every summer," Ella replies.

"Maybe they just thought you were one of his. Lovers?" John questions.

Ella and Mycroft give him the same exact stare. "Right. I'm guessing that was a stupid question," John says, sheepishly. "I can assure you Dr. Watson, it's nothing like that," Mycroft replies.

"You guys have the same exact look. How?" John asks. "Well, my mother and Mycroft have been going out for three years. Just got engaged a month ago so I guess I picked up a few things from him," Ella replies.

"An engagement that I was not made known of?" Sherlock asks. "I didn't think you'd be interested in my private life. Furthermore, I did come to tell you but you put me off rather rudely stating: 'I don't want to get into your petty affairs.' Obviously, you didn't think I had gotten engaged. Now back to business. I need you to watch over your niece for the next three months. I have a matter to attend to in Brazil and Andrea is in the states at the moment—,""But Dad! I'm 17! Why do I need a babysitter?" Ella complains.

He looks at her sternly.

"You're acting like a child. It's high time you grow up," Mycroft tells her.

He flinches a little after he says that but only Ella catches it.

She rolls her eyes but she visibly deflates as if what he said truly hurt her. Of course, only Sherlock notices it. Mycroft sighs.

"Mother is stupid. She takes my brothers but leaves me behind. Isn't that just great?" Ella huffs.

"Don't insult your mother, Ella. She's only doing what's best for you. I hope you realize that she's exactly like you, Sherlock," Mycroft tells him.

"Shall I call you Uncle Sherlock?" Ella asks, rolling her eyes.

John lets a laugh, not even bothering to hold it in.

"It's only for three months. She has her license, her own car and her own money. All she needs is a place to stay," Mycroft says.

Sherlock looks his "niece" over and sighs.

"Fine. You'll be taking John's old room. It's right up the stairs," Sherlock says. Ella stands and faces Mycroft.

"I'll be off then," he tells her. She smiles at him. "I'll text you later, Mycroft. I'll also text mum but considering the time difference I'll just wait a few," Ella tells him.

He nods and without further ado, he leaves.

"So. Bags?" John asks. "Yeah. It's in my car. I'll grab them," Ella says, also leaving.

"A niece. How you feel about that?" John asks. "Shouldn't feel any different. She's not related by blood and she off-handedly calls Mycroft dad. It's like she doesn't realize what she's doing when she calls him dad. Mycroft seems quite happy when she does though. Don't understand the sentiment.

What a strange thing. Mycroft being a step-father.

Anyway, I don't see Ella calling me uncle anytime soon. I think she'll be very useful. Since you're busy with Elizabeth, she can accompany me on cases that you can't," Sherlock explains, fiddling with his violin.

"No! You are not taking a 17 year old to a crime scene!" John says, pointing his finger at Sherlock.

"Like you so loudly pointed out, she's 17. I don't see a problem with that. Besides, Mycroft said she's just like me. Who knows, maybe she'll enjoy a good murder," Sherlock replies, playing the Violin version of Fur Elise.

"What are you even playing?" John asks tiredly.

"Fur Elise isn't it? I've never heard it played on a violin before. It's mostly because that piece was composed using the piano," Ella voices from the door. Sherlock smiles slightly. "Yes it is actually. Go right on up. The door should be open," Sherlock informs her.

She nods and carries her two duffle bags and backpack upstairs.

"You like her," John points out. "Caring is not an advantage," Sherlock replies. "And your brother said the same exact thing but look who's married with six step kids," John points out.

Sherlock stops playing.

"'All lives are lost. All hearts are broken. Caring is not an advantage' were his exact words and yet, here he is, engages to a woman with six kids. I've learned not to listen to my brother," Sherlock replies.

"Well, give me a deduction, then. Start… Showing-off," John says.

"She's 17, turning 18. Just finished schooling, at least secondary school.

She, as I stated early, off-handedly calls Mycroft dad but during other times she calls him Mycroft. She's slowly making the transition into accepting him as her new father. By all means, she's already accepted him into the family but not entirely as a father figure. That means her father is still alive and that her mother left their father. It usually takes a longer transition to call someone else father when you've got another father that you love. Love. Such a sentimental term. So hateful.

She's a Kane. Both sides of her family is the greatest families to exist. Their marriage made them more powerful then the queen. They had six children and split up when Ella was 8. Big thing in the newspaper apparently. The 2 eldest and Ella live with their mother and the three middle children live with their father but Ella is a daddy's girl.

Her mother doesn't take Ella on trips because she's afraid Ella can't handle herself. She has the two eldest with her so it's expected to think the the youngest child can't take care of herself. Ella is one of the few that don't give a damn about what other people think about her but she's also one to take criticism to the heart," Sherlock replies.

"And where do you get all this information?" John asks, surprised about the long deduction.

"A few parts, the family parts, I've seen on the news at least once in my life-time. They're a wealthy family; they're on the news a lot. I know Ella doesn't give a damn about what other people think because of the way she speaks and acts around complete strangers. Criticism hurts her especially when it comes from someone she cares about.

Earlier this evening, Mycroft told her to grow up. She acted as if it wasn't important but her aura-""Aura?""-Yes, aura, stick with the program John-deflated and so did her posture. It's like she was told that she was the worst person on this earth and shouldn't be alive anymore. She takes criticism hard," Sherlock replies.

"Only with family. Family is supposed to make you feel important and loved not critiqued at every step. Mycroft knows that I feel that way but sometimes he just can't stop himself," A voice says from the doorway.

"How long were you standing there?" John asks Ella. "Start showing off," she replies, taking a seat. "So the whole conversation. Did I get anything wrong?"Sherlock asks. "Spot on," Ella tells him.

"And you're okay with being talked about behind your back?" John asks. "Doesn't matter to me as long as it isn't lies," Ella replies.

They're interrupted by the door opening.

"Sherlock. We need you," the grey haired, detective inspector announces.

"Not taking anything less than a five today, Lestrade," Sherlock says, picking up his violin again. "Five murders, all men with curly brown hair about 6' with smiley faces carved in their abdomen. All found in the same area," Lestrade tells him.

"Do all of them have blue eyes as well?" Ella asks.

Lestrade turns to her in surprise. It's as if he's just noticing her now.

"Yeah, actually they do. Hold on. Who are you again?" Lestrade asks.

"I'm Mycrofts daughter, Ella" Ella replies.

"Your brother has kids?" Lestrade asks Sherlock, thoroughly surprised. "Step kids," Sherlock tells him.

"You're obviously here because you think the murders are connected to Sherlock because all the victims generally look like him. Am I right?" Ella asks excitedly.

"They're murders. Don't get too excited," John murmurs.

Ella deflates a little.

"Not good?" She asks. "A bit not good, yeah," John replies, her question reminding him of Sherlock.

"Actually, your spot on. Are you sure she isn't yours, Sherlock? Curly black hair, blue eyes, Cupid bow lips. She could pass as yours," Lestrade jokes.

"Murders?" John asks, irritably.

"Oh. Right. Will you come?" Lestrade asks.

"Can I come? Always wanted to see one of these!" Ella inputs excitedly.

"No""Sure" John and Sherlock reply at the same time.

Ella looks confused as Sherlock and John glare at each other.

"Is that a yes or a no?" Ella asks.

"As a parent of a daughter, I say no," John tells her.

"As your uncle, I say yes," Sherlock contradicts.

They all turn to Lestrade.

He sighs.

"It's fine as long as she doesn't touch anything," Lestrade tells them.

Ella smiles and runs downstairs, grabbing her jacket and keys.

The men follow suit.


	2. Andrew Kane

"Where's the crime scene Lestrade? We'll meet you there," Sherlock asks as he takes Ella's offered car keys.

"Shakespeare's Globe," Lestrade replies. Sherlock nods and the three of them get into Ella's car. What usually takes 14 minutes takes Sherlock nine.

"Do you drive often?" Ella asks as she tries to calm her stomach down and stop it from reaching her throat. "Not much. Why?" John asks her. "Just being curious," she says.

The three of them get to the globe to see it blocked off.

"The Freak's here. Why?" Sergeant Sally Donovan asks. "You know why. You don't strike me as stupid. Use your brains and make a deduction," Ella voices.

Sally turns her brown eyes toward her.

"And who is this, freak? Your daughter," Donovan scoffs.

"Step niece actually. My step-father is Mycroft, who I'm sure you know works in the British Government. My real father is Andrew Kane. You know, your boss. I think I need to give him a call about New Scotland Yard. It seems to me that his workers are as incompetent as monkeys on a good day, Sergeant Donovan," Ella replies, coolly.

"I'm not scared of you, kid," Sally replies.

"I didn't say you were. I'm just saying that if the need arises, my dad is on speed dial and you know what they say about the youngest child: they get everything," Ella tells her nonchalantly.

Donovan huffs and walks away.

"Sherlock, don't tell me you've insulted Donovan. You've only been here for a minute!" Lestrade exclaims, walking over to them and lifting the tape so they could go in.

"Actually, that was me. I'm sorry, I didn't introduce myself properly. I'm Ella Kane," Ella tells him, sticking out her hand.

"Greg Lestrade," he replies, taking her hand in his. He pauses as he catches on to what she just said. "Hang on. Did you say Kane?" He asks. "Youngest of the bunch," she replies.

"Ooh. I don't think you should be here. Your father would be very cross with me," Lestrade tells her.

"He doesn't need to know," Ella replies.

"But he will because he's going to be on the crime scene any second now," Lestrade says, looking at his watch nervously.

"Sorry. I'm lost," John interrupts.

"My dad is the Chief Superintendent. He got the job a few months ago. Still runs the business but most of the work load was passed off to my brothers. He doesn't like me being on crime scenes-,""and yet here you are," a voice interrupts.

Ella turns to see her father. It's obvious that she gets most of her looks from him. He's 6'4" with bright blue eyes, a straight but slightly turned up nose, Cupid bow lips and wavy black hair. He's also Lestrade's size but with a bit more muscle. His face is unreadable and looks to be about the age of 45. Ella is definitely his daughter.

"Why are you here? Aren't you supposed to be with Mycroft?" Andrew asks her.

He and Mycroft have met a few times. All of those meetings, Ella was there. They're not exactly friends, but they're not exactly enemies either. Andrew is alright with Mycroft seeing Andrea. He's happy to see her happy. The only reason they put whatever differences aside is because of Ella.

"He had urgent business in… You know. I don't even know where he's off to," Ella says shrugging.

"Brazil," John supplies.

"Oh, that's right. Brazil," Ella pipes up, smiling brightly at her father.

"And why are you here?" He asks her.

She shuffles a bit, hands held behind her back.

"Well, I wanted to see a real crime scene and since I'm saying with Mycroft's brother, the great Sherlock Holmes, I thought that this'll be a great opportunity and-,"

"What did I say about getting involved with things that you shouldn't even know about?!" Andrew snaps and Ella straightens. "You shouldn't even be with him. If Mycroft weren't going to be with you for the summer, he should've sent you with me! You know how I hate you being in dangerous situations! I've told you a dozen times to stay away from crime scenes because there's always the possibility that you could get hurt! Sometimes, I really think you're so damn stupid!"

She backs away as if he just slapped her across her face. "I-," Andrew starts. Ella turns around and walks away. "Ella!" Andrew calls out. She ignores him and keeps on walking.

He sighs.

"Shall we proceed?" Lestrade asks. Andrew nods and they all head in.

"Do you do that often? Insulting your daughter and such," Sherlock asks, taking out his magnifying glass. "Sherlock-," "That is none of your business, Mr. Holmes," Andrew interrupts John. "Considering the fact that she's in my care for the next three months, it is my business," Sherlock tells him. "Which she shouldn't be," Andrew argues. "But she is. Is that why you and your wife got a divorce? Is it because you always insult Ella and your wife couldn't handle a good for nothing husband? What-," Sherlock starts to stay.

Andrew pushes him against the wall, constricting his breathing. "I can tolerate Mycroft but I cannot tolerate your attitude towards me. Don't think that you know everything about me just because you can make a few simple deductions. You know nothing of what I and my family have been through so do not call me a good for nothing husband. Now, if you'll excuse me, I have a daughter to look for. I expect a full report at the end of the day Lestrade," Andrew says, fixing his suit.

He leaves and John glares at Sherlock.

"Must you always pick a fight?" John asks him. "You've known me for years John. I am not one to keep my mouth shut," Sherlock tells him.

"Can you at least keep your mouth shut when he's around? You're lucky he's even letting you on crime scenes. Before he became Chief Superintendent, I was about to be fired for letting you on to the crime scene and arrest you for obstruction of evidence. He saved my ass and your ass as well so you'd better watch your mouth around him," Lestrade tells Sherlock.

Sherlock just ignores him and continues looking at the scene.

"He seems a bit out of character don't you think?" Lestrade asks.

"What do you mean?" John asks. "I don't know. He seems a bit, protective and friendly. He doesn't seem to be faking it either," Lestrade says. "He's been that way since-,""John! If your done with your gossiping, I need a little input," Sherlock interrupts.

John shrugs at Lestrade and goes to help Sherlock.

**REVIEW PLEASE!**


	3. A Little Chat

Sherlock, as usual was correct. When Ella was six, she had almost gotten herself killed by a car. Her father, in anger, had yelled at her and called her an idiot that shouldn't even be a part of their family. That had sent her mind spiraling. She wouldn't eat for days, never spoke, never did anything but stay in her room. She was pretty much a mute. (**A/N: I don't know if it is possible to become mute because of this but in my story it is.**) The only person to bring her out of her shell, after an entire month, was her second oldest brother, Kris.

Of course, her avoidance in eating and speaking and doing anything  
>in general raised a red flag with her family, her mother especially. Within<br>that month, she had constantly got into arguments with Andrew about Ella but  
>they'd never let their kids hear it. Once she began talking again, everything<br>seemed to go back to normal until Andrew had threw another insult at Ella. 

Instead of just a month, it was an entire year and it was Kris who  
>bought her back to normal again. She did eat. She just didn't speak to people.<br>Her first words after an entire year was to her mother, "_I don't want a daddy  
>like that.<em>" 

And just like that, after 24 years, their marriage was over. 

It was automatically decided that Ella would go with Andrea. It  
>was pretty much written in stone. Andrew felt and knew that he wouldn't be able<br>to contain himself and only make Ella's mental state worse. Andrea had also  
>gotten Kris and Ian, the oldest, because those two are stuck together like glue<br>and Andrea knew that Ella only depended Kris most of the time.

That's how it ended. Andrea Gale, formerly Kane, moving out with  
>her three kids, Ian, Kris and Ella and Andrew living with his three other sons,<br>Evan, Caesar and Gregory. 

_**Currently, with Ella.**_

'Still didn't learn after all these years,' Ella thinks to herself  
>as she makes her way through the streets of London, 'what a stupid mistake.<br>Stupid Ella! Nice going. You left your keys with Sherlock! Where are you going  
>to go now?' Her phone rings. She answers it as soon as she reads the caller ID. <p>

"Why are you calling? Is mom alright? What's wrong?" Ella asks  
>frantically. <p>

She's answered with a chuckle.

"Calm down, Ells. Mom is fine. Can't I just call my favorite sister?" Kris asks her. "I'm your only sister," she says, pointedly, "besides, it's 2:30pm here and that means its 4:30am there. You are never an early riser. Never have been and never will be and you sound tired. Dad called you didn't he?" she asks. "I can never sneak anything past you," he tells her. "Never," she says, smiling. 

She stops and looks at what street she's at. She's actually in front of Miyama's restaurant. "Where-," Kris starts. "I'm in front of Miyama's. I'm headed to Bart's on foot because I forgot my keys with Sherlock," Ella interrupts, walking straight and turning left on St. Paul's Churchyard. (**PS. These are actual directions I found on Google Map**. 

"Mycroft's brother Sherlock?" 

"The one and only. Dad blew his top when he caught me at the crime scene and spouted nonsense on how I should've stayed with him instead of Sherlock if Mycroft was going out of country," she explains, following the path. 

"Is he insane?"

"Obviously," She replies, rolling her eyes. 

"How is it, staying with Sherlock?" Kris asks. "It's interesting. He's exactly like Mycroft described him. He read everything about me as soon as he stepped into the room. He wasn't too excited about my having to stay with him at first. Well, I THINK it's 'at first'. I haven't got a chance to know him better. We've only known each other for three hours. We've got three months left," Ella tells him.

"So how did dad catch you on the crime scene?" Kris asks. "Well, Sherlock got called in to investigate because the people who were murdered look similar to him. I asked to go. Sherlock said yes and John said no. And before you ask, yes, I'm talking about John Watson, Sherlock's old roommate. Anyway, Inspector Lestrade said yes but that was before he found out I was a Kane. That's how dad caught me," she tells him, taking a right at Ave Maria Lane.

"Maybe you shouldn't go on Crime Scenes this summer," Kris suggests. "And stay home with Sherlock and Mrs. Hudson all summer? No thanks," she says. "But going on crime scenes is staying with Sherlock," Kris points out. "There's a difference," Ella replies, taking a left up Newgate Street. She walks fast.

"Whatever you say. Look, I'm tired. I'll check up on you later. Love you," Kris says, yawning. "Love you too. Bye," Ella says. They both hang up. Ella continues to make her way to St. Bart's. She's got it memorized in her brain. She checks her phone. 10 missed calls from her dad. 'Not going to call him back,' she thinks.

She looks at her texts. 10 from her dad. She ignores all of them. She looks at her other message. "I'm sorry. I didn't mean to. Please. I'm miss you," a text message from a person named Jordan.

Maybe it's a guy. Maybe it's a girl. It's obvious it's her other half. Well, it used to be her other half.

"Look, Jordan, I liked you a lot but you cheated. I don't need a guy like that in my life. Besides, dad doesn't like you," she texts him. She looks up and there she is, in front of St. Bart's.

She continues up the stairs to look for her Aunt Molly.

**A/N: Yeah. That last part was as random AF but I don't know where I'm headed with this chapter. At least you got some background of my character. I don't know where this is going to be honest so I don't know when the next update will be. Please review!**


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